This invention relates generally to photographic equipment and particularly to a device for adapting a conventional process or copy camera so that it can be used to expose smaller film.
Photographic equipment of the type known interchangeably as a process camera or copy camera is used extensively in many commercial applications for exposing relatively large sheets of film. Able to achieve precise focusing and high resolution, these cameras and their copy-holding components take up the space of a small office while offering the facility for producing blueprints or large copies of other subject material.
Like the cameras we use for taking snapshots at home, a lens is used to focus an image along a light-tight optical path and through a frame opening to expose film mounted over the opening. Unlike the equipment we use at home, the process camera is considerably scaled up in size to expose sheets of film on the order of 20.times.30 inches or larger through a frame opening having the same general size.
The camera back itself is a six-foot-tall rigid panel that stands directly on the floor to define a frame opening at the four-foot level within easy reach of an operator behind the camera back. A sheet of film is placed over this frame opening for exposure with the aid of a small door mounted on the camera back. This is done with the lights extinguished by first placing the film against the door where it is sucked in place by a light vacuum, and then swinging the door closed over the frame opening. The film is then exposed in this position with an image directed through the frame opening from the front side of the camera back.
The subject to be photographed, or copy, is held at just the right distance on the front side of the camera back by adjustable copy-holding components that extend forward of the camera back some nine feet or so. An adjustable camera bellows extends from the frame opening toward the copy to the lens, and these components are adjusted from behind the camera back with a remote control unit to focus the desired image.
Thus, precise focusing and high resolution is achieved in a convenient-to-operate arrangement.
This arrangement works well in many situations, but it has certain drawbacks. For example, it does not lend itself to the use of smaller, less expensive film in those situations not requiring a large sheet of film, the frame opening being in the wrong focal plane for focusing on means of mounting smaller film such as is contained within a standard sheet film holder, roll film back, or polaroid back. Among other things, use of this other film would enable various prints to be inexpensively made. A 4.times.5 film size, for example, would permit use of a standard 4.times.5 enlarger with its capability to produce various sizes and quantities of prints. In addition, exposure tests and even final photographs could be made if the camera were adaptable to use with a standard polaroid film back. Also, the lights would not have to be extinguished to avoid unwanted film exposure.
Consequently, it is desireable to have an adapter for a process camera that would alleviate these drawbacks and enable exposure of smaller film, such as that within a standard sheet film holder, roll film back, or polaroid film back.
And it is desireable that the adapter be conveniently mounted on the camera and enable easy placement and removal of the smaller film to be exposed.